Unknown gunmen kill one rivers

I apologize, but it seems like there may be a mistake in your message. It appears that the phrase "unknown gunmen kill one rivers" doesn't make sense. Rivers are bodies of water, and they cannot be killed. Additionally, the term "gunmen" typically refers to individuals who use firearms, but it's unclear what they would be targeting in this scenario.

Could you please provide more context or clarify what you meant to say? I'm here to help and provide assistance to the best of my abilities.